CVE-2026-74222: U-Boot before 2026.10-rc5 Use-After-Free in lwIP wget Receive Callback

Severity: high (CVSS 8.2 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.3% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2026-09-29 · updated 2026-10-02
Weakness: CWE-416

Description

U-Boot before 2026.10-rc5 contains a use-after-free vulnerability in the httpc_recv_cb() function within the lwIP wget implementation. When HTTP data storage fails, the callback frees the connection PCB but returns ERR_BUF instead of ERR_ABRT, causing the TCP input path to access released memory and crash the bootloader.

Affected products

u-boot: before 2026.10-rc5 — fixed in 2026.10-rc5

How to fix

Upgrade to a fixed version: u-boot 2026.10-rc5. Check the vendor advisory for mitigations.

References

https://github.com/u-boot/u-boot
https://github.com/u-boot/u-boot/blob/v2026.07/net/lwip/wget.c#L194
https://github.com/u-boot/u-boot/commit/2d94618a58aeb7630f18eee33419ce48d0fd3616
https://www.vulncheck.com/advisories/u-boot-before-2026.10-rc5-use-after-free-in-lwip-wget-receive-callback

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